I'm New I had this crazy idea to create a Missile Defense System using an Arduino. For the missile I would use a nerf dart and build the turrets with the firing capability out of parts around the house. These turrets would be on servos with a sensing mechanism that will shoot down any flying device it detects. Question I had was, Can you program an Arduino to sense any flying object on its own? I was also thinking of using remote control helicopter to see in fact the missle defense system can shoot down the helicopter. Any suggestions? or am I way off topic for this project.
For the sensing system look around for so kind of system that can attach to Arduino like IR sensors or something. The ardunio cannot detect movement by itself, it requires some sort external attachment/sensor.
This is just a google search but can give a good start point for motion sensors for Arduino.
You would probably have better luck with a servo pan & tilt sonar module like this: Pololu - Parallax PING))) Ultrasonic Sensor #28015 and a laser range finder to pinpoint the target. You program the arduino to translate the position of the pan & tilt assembly (which you have to build using RC servos) into a coordinate system. Your servos
0 position represents a reference point. When you command the servo to move, you increment/decriment a position variable to keep track of where the sonar is pointing. You have a separate pan & tilt (2 servos) assembly for the laser range finder but the range finder gives you range so you program the arduino not to fire until the range is close enough to hit the target. You display your
sonar and laser range finder positions on separate lcds.